The present invention relates to an automatic clutch control system for use in automobiles, more particularly to a method and an apparatus, using a microcomputer, which enable an automatic clutch to be controlled when a clutch control sensor is out of order.
The present invention can automatically diagnose the condition of the clutch stroke sensor and, in the event of a breakdown of the clutch stroke sensor, can automatically perform a back-up process for automatic clutch control.
Automatic clutch control systems using microcomputers have already been proposed, such as in Japanese Examined Patent Publication (Kokoku) No. 50-12648 and Japanese Unexamined Patent Publication (Kokai) No. 52-5117. In these systems, a microcomputer is used to control the operation of solenoid valves under a predetermined program stored in the microcomputer, the operation of an actuator is controlled in accordance with the operation of the solenoid valves, and the movement of the clutches (for example, dry-type single-plate clutches), i.e., clutch engagement, clutch slip, and clutch disengagement, is controlled by the actuator through some link mechanism. Japanese Examined Patent Publication No. 50-12648 further discloses a method for gradually changing the clutch engagement condition in proportion to the increment of the engine rotational speed, while Japanese Unexamined Patent Publication No. 52-5117 discloses a method for changing the clutch engagement speed in response to the engine rotational speed.
In these methods, the clutch operation range is determined by the actuator stroke. The actuator stroke, on the other hand, is determined based on a stroke signal detected by the clutch stroke sensor using a potentiometer. Therefore, when the clutch stroke sensor is out of order, the clutch operation can no longer be controlled.